KR20150118211A

KR20150118211A - Electric brake system

Info

Publication number: KR20150118211A
Application number: KR1020140043298A
Authority: KR
Inventors: 양이진
Original assignee: 주식회사 만도
Priority date: 2014-04-11
Filing date: 2014-04-11
Publication date: 2015-10-22

Abstract

Disclosed is an electronic brake system. According to an embodiment of the present invention, the electronic brake system is provided to: simplify the configuration by minimizing the number of valves for controlling the hydraulic flow; provide a stable sense of pressing pedals when braking; and enable precise pressure control. According to the embodiment of the present invention, the electronic brake system, including two hydraulic units, a master cylinder and a pedal displacement sensor, comprises: a pressure supply unit connected to a reservoir by an inlet flow path to receive oil; a hydraulic control unit formed into a first and a second hydraulic circuit respectively connected to the hydraulic units; a simulation unit connected to the master cylinder; and an electronic control unit for controlling a motor and valves based on pressure information and pedal displacement information.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic brake system, and more particularly, to an electronic brake system capable of simplifying a structure and capable of precise pressure control.

The vehicle is essentially equipped with a brake system for braking. Recently, various types of systems have been proposed to obtain a more powerful and stable braking force. Examples of the brake system include an anti-lock brake system (ABS) that prevents slippage of the wheel during braking, a brake traction control system (BTCS: Brake) that prevents slippage of the drive wheels And Vehicle Dynamic Control System (VDC) that maintains the driving condition of the vehicle by controlling the brake hydraulic pressure by combining anti-lock brake system and traction control.

Such an electronic brake system includes a plurality of solenoid valves for controlling braking hydraulic pressure transmitted to a wheel cylinder (hydraulic brake) side mounted on a wheel of a vehicle, a pair of low pressure accumulators for temporarily storing the oil that has escaped from the wheel cylinder, An accumulator, a motor and a pump for forcibly pumping the oil of the low pressure accumulator, a plurality of check valves for preventing reverse flow of the oil, and an electronic control unit (ECU) for controlling the driving of the solenoid valve and the motor These components are compactly built into hydraulic blocks made of aluminum.

The structure of such an electronic brake system is disclosed in Patent No. 10-1090910. According to the disclosed document, since the electronic brake system is configured to drive the motor and the pump to the high-pressure and / or low-pressure accumulator to fill the hydraulic pressure, and to control the pressure of the hydraulic pressure by the opening and closing of the electromagnetic solenoid valve, There is a problem.

Further, in a system using an accumulator, noise is generated when oil is stored in an accumulator, and controllability using a solenoid valve is deteriorated.

In addition, since there is a predetermined gap between the input rod for pressing the master cylinder and the piston provided in the master cylinder according to the brake force of the brake pedal, the pedal stroke ineffective interval corresponding to the non-operation gap of the system is generated, I feel like I'm not braking, I have a problem that can cause complaints or safety accidents. Also, there is a problem that the feeling of the pedal is deteriorated.

Registered patent KR 10-1090910 (Mando Co., Ltd.) Dec. 1, 2011

The electronic brake system according to an embodiment of the present invention minimizes the number of valves for controlling the flow of hydraulic pressure to simplify the configuration, provide stable pedal brakes during braking, and enable precise pressure control.

In addition, even if the brake system is operated abnormally, the braking is performed by the driver's pressing force, and the pressure can be formed immediately without an invalid stroke interval corresponding to the pressing force of the brake pedal.

According to an aspect of the present invention, there is provided a hydraulic brake system comprising: a master cylinder having two hydraulic portions connected to two wheels respectively and coupled with a reservoir to receive oil; and a brake pedal connected to an input rod for transmitting a force, An electronic brake system comprising a pedal displacement sensor for detecting a displacement, the electronic brake system comprising: an oil passage connected to a reservoir by an oil passage to receive oil; an electric signal is outputted through the pedal displacement sensor to output an electric signal, A pressure supply device for converting the rotational force of the motor into a linear motion; A hydraulic control unit formed of first and second hydraulic circuits respectively connected to the two hydraulic units, the hydraulic control unit comprising a plurality of valves for controlling the braking operation by receiving hydraulic pressure by a force generated by the pressure supply device; A simulation device connected to the master cylinder and configured to provide a reaction force in response to the power of the brake pedal; And an electronic control unit for controlling the motor and the valves based on the pressure information and the pedal displacement information, wherein the hydraulic control unit is arranged on the upstream side of the wheel cylinder of each wheel to control the delivery of the hydraulic pressure to the wheel cylinder A first switching valve and a second switching valve respectively provided in a flow path connecting the pressure supply device and each of the hydraulic circuits to control the hydraulic pressure transmitted to the wheel cylinder by an opening and closing operation, Closed first and second dump valves connected to the downstream side and connected to the two wheels and the reservoir in each hydraulic circuit to control the escape of hydraulic pressure from the wheel cylinder.

In addition, each of the dump valves may be connected to the inflow channel through a return channel connected to the reservoir.

The first and second backup oil channels connect the two hydraulic pressure units and the two hydraulic circuits respectively to supply the oil directly to the wheel cylinders when the electronic brake system operates abnormally. And further includes first and second shut-off valves provided in the flow paths to control the flow of the oil.

In addition, the first and second shut-off valves may be provided as normally open solenoid valves that are opened in a normal state and operate to close the valve upon receiving a close signal from the electronic control unit.

A first hydraulic oil path connecting the pressure supply device and the first hydraulic circuit and a second hydraulic oil path branched from the first hydraulic oil path and connecting the second hydraulic circuit, And the second switching valve is disposed in the second hydraulic oil path so that the hydraulic pressure flowing to each hydraulic circuit can be independently controlled.

In addition, check valves may be provided in parallel to the first and second switching valves.

In addition, the first and second switch valves may be provided as normally closed solenoid valves which are closed in a normal state and operate to open the valve when an open signal is received in the electronic control unit.

The pressure supply device may further include: a pressure chamber connected to the inflow channel and supplied with oil; A hydraulic piston provided in the pressure chamber; A hydraulic spring provided in the pressure chamber and elastically supporting the hydraulic piston; A motor for generating a rotational force by an electrical signal of the pedal displacement sensor; And a ball screw member composed of a screw and a ball nut for converting the rotational motion of the motor into a linear motion, wherein the hydraulic piston is connected to a ball nut that linearly moves, and presses the oil in the pressure chamber by a ball nut Lt; / RTI >

In addition, a check valve may be installed in the inflow channel so as to prevent the pressure of the pressure chamber from flowing backward, and to allow the oil to be sucked into the pressure chamber when the hydraulic piston is returned.

In addition, a pressure sensor for sensing a pressure may be provided in the pressure chamber and the flow path connected to the master cylinder.

A cut-off hole may be formed in the pressure chamber, and a connection path may be formed between the pressure chamber and the inflow path, wherein the cutoff hole and the inflow path are connected to each other.

The simulation apparatus may further comprise: a simulation chamber for storing the oil flowing out from the master cylinder; a pedal simulator having a reaction force piston provided in the simulation chamber and a reaction force spring for elastically supporting the reaction force piston; And a simulation valve provided at a rear end of the pedal simulator, wherein the simulation valve is connected to a reservoir and can be filled with oil inside the simulation chamber through the simulation valve.

In addition, the simulation valve may be provided as a normally closed solenoid valve that is operated to open the valve when it is closed in the normal state and receives an open signal in the electronic control unit.

Further, a simulation check valve is further provided between the pedal simulator and the simulation valve, and the rear end pressure of the pedal simulator according to the power of the brake pedal is transmitted only through the simulation valve. When the brake pedal is released, So that the oil can be sucked and stored in the simulation chamber.

In addition, in the master cylinder, the first and second pistons are arranged to be spaced apart from each other so as to press the two hydraulic portions, respectively, and the first piston is brought into contact with the input rod to prevent a gap between the first piston and the input rod Lt; / RTI >

The electromagnetic brake system according to the embodiment of the present invention has an advantage that the structure can be simplified compared to the conventional one by minimizing the number of valves for controlling the flow of hydraulic pressure. Accordingly, the size of the brake system, that is, the size of the modulator block in which the valves are installed, can be reduced, thereby realizing a low-cost type.

Further, there is an effect that precise pressure control can be performed by controlling the motor and the valves in cooperation with each other. In addition, each of the two hydraulic circuits is independently controlled to be connected to two wheels, and the control range is increased by interlocking the pressure supply device according to the pressure and priority logic required for each wheel There are advantages to be able to.

In addition, when the brake system malfunctions, the driver's power is directly transmitted to the master cylinder, thereby enabling braking of the vehicle, thereby providing a stable braking force.

In addition, it is possible to remove the predetermined gap formed between the input rod that pressurizes the master cylinder and the piston provided in the master cylinder so that pressure can be formed immediately without an invalid stroke interval corresponding to the pressing force of the brake pedal, There is an advantage that the pedal feeling transmitted to the driver can be kept stable even if the pressure is arbitrarily adjusted during braking.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described in detail with reference to the following drawings, which illustrate preferred embodiments of the present invention, and thus the technical idea of the present invention should not be construed as being limited thereto.
1 is a hydraulic circuit diagram showing a non-synchronized state of an electronic brake system according to a preferred embodiment of the present invention.
2 is a hydraulic circuit diagram showing a state in which an electronic brake system according to a preferred embodiment of the present invention operates normally.
3 is a hydraulic circuit diagram showing a state of independently controlling the hydraulic pressure supplied to the wheel cylinder through the hydraulic control unit of the electronic brake system according to the preferred embodiment of the present invention.
4 is a hydraulic circuit diagram showing a state in which the electromagnetic brake system according to the preferred embodiment of the present invention operates abnormally.
5 is a hydraulic circuit diagram showing an electronic brake system according to another preferred embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a hydraulic circuit diagram showing a non-synchronized state of an electronic brake system according to a preferred embodiment of the present invention.

Referring to the drawings, an electronic brake system typically includes a master cylinder 20 for generating hydraulic pressure, a reservoir 30 coupled to the upper portion of the master cylinder 20 for storing oil, An input rod 12 which pressurizes the master cylinder 20 in accordance with the displacement of the wheel cylinder 40 and the brake pedal 10 to which the hydraulic pressure is transmitted to perform braking of the respective wheels RR, RL, FR and FL, And a pedal displacement sensor 11 for detecting the pedal displacement.

At this time, the master cylinder 20 may be constituted by at least one chamber so as to generate hydraulic pressure. However, as shown, the first piston 21a and the second piston 22a are formed to have two hydraulic pressure portions And is in contact with the input rod 12. The master cylinder 20 has two hydraulic pressure portions in order to ensure safety in the event of a failure. For example, the first hydraulic pressure portion of the two hydraulic pressure portions is connected to the right front wheel FR and the left rear wheel RL of the vehicle, and the remaining hydraulic pressure portion is connected to the left front wheel FL and the right rear wheel RR. Alternatively, the first hydraulic section of the two hydraulic sections may be connected to the two front wheels FR and FL and the remaining hydraulic section may be connected to the two rear wheels RR and RL. The independent construction of the two hydraulic pressure portions as described above is intended to enable braking of the vehicle even in the event of failure of one hydraulic pressure portion.

The first piston 21a and the second piston 22a of the master cylinder 20 are provided with a first spring 21b and a second spring 22b. The first spring 21b and the second spring 22b compress the first piston 21a and the second piston 22a to store the elastic force. This elastic force pushes the first and second pistons 21a and 22a backward when the pushing force of the first piston 21a becomes smaller than the elastic force.

On the other hand, the input rod 12 for pressing the first piston 21a of the master cylinder 20 is in contact with the first piston 21a, so that the gap between the master cylinder 20 and the input rod 12 does not exist. That is, when the brake pedal 10 is depressed, the master cylinder 20 is directly pressed without a pedal invalid stroke section.

The electronic brake system according to the present invention includes a pressure supply device 110 that receives mechanical signals from a pedal displacement sensor 11 for sensing the displacement of the brake pedal 10 as an electric signal and operates mechanically, A hydraulic control unit 120 that performs braking of the wheel with a force generated by the apparatus 110 and a simulation apparatus 150 that is connected to the master cylinder 20 and provides a reaction force to the brake pedal 10 .

The pressure supply device 110 includes a pressure chamber 111 in which a predetermined space is formed to receive and store the oil, a hydraulic piston 112 and a hydraulic spring 113 provided in the pressure chamber 111, a pedal displacement sensor 11, And a ball screw member 115 composed of a screw (not shown) and a ball nut (not shown) for converting the rotational motion of the motor 114 into a rectilinear motion do. At this time, the reservoir 20 and the pressure chamber 111 are connected by the inflow passage 116 to supply the oil to the pressure chamber 111. Here, the signal sensed by the pedal displacement sensor 11 is transmitted to an electronic control unit (ECU) (not shown), and the electronic control unit controls the motor 114 and the valves provided in the electronic brake system of the present invention do. The operation in which a plurality of valves are controlled according to the displacement of the brake pedal 10 will be described below.

The pressure chamber 111 is connected to the reverberator 30 by the inflow channel 116 as described above, and receives and stores the oil. In the pressure chamber 111, a hydraulic piston 112 and a hydraulic spring 113 for elastically supporting the hydraulic piston 112 are provided. The hydraulic piston 112 is brought into contact with the ball nut of the ball screw member 115 to press the pressure chamber 111 by the linear movement of the ball nut and the hydraulic spring 113 is urged by the hydraulic pressure And serves to return the piston 112 to its original position.

The motor 114 is an electric motor that generates a rotational force through a signal output from the electronic control unit, and generates a rotational force in the forward or reverse direction by the electronic control unit. At this time, the screw of the ball screw member 115, which converts the rotational force into a linear motion, acts as a rotation axis of the motor 114 and also linearly moves the ball nut. Although not shown, a spiral groove is formed on the outer circumferential surface of the screw, and the ball nut is coupled through the spiral groove and the plurality of balls. That is, as described above, the hydraulic piston 112 is pressed by the linear motion of the ball nut to generate the hydraulic pressure, and it is possible to perform precise control by controlling the rotation angle or speed through the motor 114. At this time, the ball screw member 115 is a device for converting a rotational motion into a linear motion and is a well known and well-known technology, and thus a detailed description thereof will be omitted.

According to the present invention, the check valve 117 is provided in the inflow passage 116 to prevent the pressure of the pressure chamber 111 from flowing backward. The check valve 117 serves to prevent the pressure of the pressure chamber 111 from flowing backward and allows the oil to be sucked and stored in the pressure chamber 111 when the hydraulic piston 112 is returned.

When the electromagnetic brake system having the pressure supply device 110 as described above is used, the pressure piston 112 is returned and the pressure in the pressure chamber 111 is released to the atmospheric pressure in the process of absorbing the oil in the pressure chamber 111 It can be configured to prevent the occurrence of a failure. A cutoff hole 119 is formed in the pressure chamber 111 and a cutoff hole 119 and an inflow passage 116 are connected between the pressure chamber 111 and the inflow passage 116, Is formed. At this time, the cutoff hole 119 is formed at a position corresponding to the initial position of the pressure piston 112. When the pressure piston 112 is returned, the pressure piston 112 is automatically connected to the reservoir 30 through the connection passage 118, so that the pressure is returned to the atmospheric pressure.

Reference numeral 'S1' is a first pressure sensor for sensing the fluid pressure of the pressure chamber 111.

Referring again to FIG. 1, the hydraulic control unit 120 includes a first hydraulic circuit 121 for controlling at least one first wheel to which braking is effected by supplying hydraulic pressure, and a second hydraulic circuit 121 for controlling at least one second wheel 2 hydraulic circuit 122 and is composed of two wheel braking circuits. At this time, the first wheel is composed of the right front wheel FR and the left rear wheel RL, and the second wheel can be composed of the left front wheel FL and the right rear wheel RR. Each of the wheels FR, FL, RR, RL is provided with a wheel cylinder 40, and is supplied with hydraulic pressure to perform braking. That is, each of the hydraulic circuits 121 and 122 includes a passage connected to the wheel cylinder 40, and a plurality of valves 123, 125, 126, 133 and 134 for controlling the hydraulic pressure are installed in these passages.

The plurality of valves 123, 125, 126, 133 and 134 are disposed on the upstream side of the wheel cylinder 40 and are connected to the wheel cylinder 40 through a normally open type A solenoid valve 123 and a pressure supply device 110 and respective hydraulic circuits 121 and 122 so as to control hydraulic pressure transmitted to the wheel cylinder 40 by opening and closing operations Is connected to the downstream side of the first switching valve 133 and the second switching valve 134 and the switching valves 133 and 134 and is connected to the two wheels and the reservoir 30 at the respective hydraulic circuits 121 and 122 And a first and a second dump valves 125 and 126 provided as a normally closed type solenoid valve for controlling the fluid pressure to be discharged from the wheel cylinder 40. The opening and closing operations of the valves 123, 125, 126, 133 and 134 are controlled by the electronic control unit.

The hydraulic control unit 120 includes a return flow path 128 connecting the first and second dump valves 125 and 126 and the inflow path 116. The return flow path 128 is configured to transfer the fluid pressure to the reservoir 30 or the pressure supply device 110 when the hydraulic pressure delivered to the wheel cylinder 40 is discharged through the first and second dump valves 125 and 126 . At this time, the first dump valve 125 is provided in the first hydraulic circuit 121 to control the discharge hydraulic pressure of the wheel cylinder 0 installed on the two wheels FR and RL, and the second dump valve 126 controls the discharge pressure 2 hydraulic circuit 122 to control the discharge hydraulic pressure of the wheel cylinders 40 provided on the two wheels FL and RR. That is, in order to control the hydraulic pressure discharged from the conventional wheel cylinder, four out valves should be provided on the downstream side of each wheel cylinder. However, the electronic brake system according to the embodiment of the present invention includes two dump valves 125 and 126 By controlling the hydraulic pressure of the wheel cylinder 40, the number of valves is reduced as compared with the prior art, thereby simplifying the structure of the brake system and reducing the size of the brake system.

According to an embodiment of the present invention, first and second hydraulic oil passages 131 and 132 for connecting the pressure supply device 110 and the hydraulic circuits 121 and 122 of the hydraulic control unit 120, respectively. The first hydraulic oil path 131 is provided with a first switching valve 133 for controlling the transmission of the hydraulic pressure to the wheel cylinder 40 of the first hydraulic circuit 121 by the opening and closing operation, Is provided with a second switching valve 134 for controlling the transmission of the hydraulic pressure to the wheel cylinder 40 of the second hydraulic circuit 122 by the opening and closing operation. At this time, the second hydraulic oil path 132 branches from the first hydraulic oil path 131 and is connected to the second hydraulic circuit 122. The opening and closing operations of the first and second switching valves 133 and 134 are independently controlled by the electronic control unit and the hydraulic pressure generated from the pressure supply device 110 is directly transmitted to the wheel cylinder 40. That is, the first switching valve 133 controls the hydraulic pressure supplied to the first hydraulic circuit 121, and the second switching valve 134 controls the hydraulic pressure supplied to the second hydraulic circuit 122.

These first and second switching valves 133 and 134 are provided as normally closed solenoid valves that are closed in a normal state and operate to open the valve when receiving an open signal in the electronic control unit.

In addition, a check valve may be additionally provided to the first and second hydraulic oil passages 131 and 132 to prevent a pressure increase due to the operation delay of the first and second switching valves 133 and 134 as described above . For example, FIG. 5 illustrates an electronic brake system in accordance with another embodiment of the present invention. Wherein like reference numerals refer to like parts having the same functions as in the previous figures.

According to the present embodiment, check valves 135 and 136 are installed in parallel to the first and second switching valves 133 and 134 disposed at the connecting portion of the pressure chambers 111 and the hydraulic circuits 121 and 122, respectively do. The check valve includes a first check valve 135 disposed in parallel with the first switch valve 133 and a second check valve 136 disposed in parallel with the second switch valve 134. These check valves 135 and 136 are one-way check valves provided to transmit hydraulic pressure only to the wheel cylinders 40 and prevent the pressure increase due to an operation delay of the first and second switching valves 133 and 134 do.

Referring again to FIG. 1, a first backup channel 141 and a second backup channel 142, which form a flow path, are provided between the master cylinder 20 having two hydraulic pressure portions and the wheel cylinder 40 when the electronic brake system fails May be provided. A first shutoff valve 143 for opening and closing the first backup passage 141 is provided in the middle of the first backup passage 141 and a second shutoff valve 143 is provided in the middle of the second backup passage 142 for opening and closing the second backup passage 142 A second shutoff valve 144 is provided. The first backup channel 141 is connected to the first hydraulic circuit 121 through the first shutoff valve 143 and the second backup channel 142 is connected to the second hydraulic circuit 141 through the second shutoff valve 144. [ (Not shown). In particular, a second pressure sensor S2 may be provided between the first shut-off valve 143 and the master cylinder 20 to measure the oil pressure of the master cylinder 20. [ This is because the backup flow paths 141 and 142 are blocked by the first shutoff valve 143 and the second shutoff valve 144 when the driver brakes and the braking will is requested by the driver by the second pressure sensor S2 .

The first and second shutoff valves 143 and 144 are provided as a normally open solenoid valve that is opened in a normal state and operates to close the valve upon receiving a close signal from the electronic control unit.

Further, a simulation apparatus 150 connected to the master cylinder 20 and provided to provide a reaction force in response to the pressing force of the brake pedal 10 is provided. The flow path connecting the master cylinder 20 and the simulation apparatus 150 is connected to the first backup channel 141. The simulation apparatus 150 includes a simulation chamber 151 provided to store the oil flowing out from the outlet side of the master cylinder 20, a reaction force piston 152 provided in the simulation chamber 151, And a simulation valve 155 connected to the pedal simulator and the rear end of the simulation chamber 151. At this time, the simulation chamber 151 is formed to have a certain range of displacement by the oil introduced into the simulation chamber 151 by the reaction force piston 152 and the reaction force spring 153.

The simulation valve 155 is connected through the oil passage 158 to connect the reservoir 30 with the rear end of the simulation chamber 151. At this time, the oil passage 158 is connected to the inflow passage 116 connected to the reservoir 30. The inlet of the simulation chamber 151 is connected to the master cylinder 20 and the rear end of the simulation chamber 151 is connected to the simulation valve 155. The simulation valve 155 is connected to the oil passage 158, The simulator chamber 151 is connected to the return flow path 128 and the inflow path 116 connected to the reservoir 30 through the pedal simulator.

This simulation valve 155 is constituted by a normally closed type solenoid valve that keeps the normally closed state and opens when the driver depresses the brake pedal 10 to transfer the brake oil to the simulation chamber 151.

A simulation check valve 157 is provided between the simulation apparatus 150 and the master cylinder 20, that is, between the simulation chamber 151 and the simulation valve 155. The simulation check valve 157 is connected to the reservoir 30 to flow into the simulation chamber 151. The simulation check valve 157 is made such that the pressure according to the power of the brake pedal 10 is transmitted to the simulation chamber 151 only through the simulation valve 155. That is, the reaction force piston 152 of the pedal simulator compresses the reaction force spring 153, and the oil in the simulation chamber 151 is transferred to the reservoir 30 through the simulation valve 155 and the oil passage 158. Therefore, since the oil is filled in the simulation chamber 151, the friction of the reaction force piston 152 is minimized during operation of the simulation apparatus 150, so that the durability of the simulation apparatus 150 is improved. In addition, And has a blocked structure.

In addition, as oil is supplied to the simulation chamber 151 through the simulation check valve 157 upon release of the pedal force of the brake pedal 10, a fast return of the pedal simulator pressure is assured.

Hereinafter, the operation of the electronic brake system according to one preferred embodiment of the present invention will be described in detail.

2 is a hydraulic circuit diagram showing a state in which the electronic brake system operates normally.

Referring to FIG. 2, when the braking by the driver is started, the amount of brake demand of the driver can be sensed through the pedal displacement sensor 11 through information such as the pressure of the brake pedal 10 depressed by the driver. An electronic control unit (not shown) receives the electric signal output from the pedal displacement sensor 11 and drives the motor 114. The electronic control unit controls the amount of regenerative braking through the second pressure sensor S2 provided at the outlet side of the master cylinder 20 and the first pressure sensor S1 provided at the outlet side of the pressure supply device 110 And the magnitude of the frictional braking amount can be calculated according to the difference between the demand braking amount and the regenerating braking amount of the driver so that the magnitude of the pressure increase or the pressure decrease of the wheel side can be grasped.

Specifically, when the driver depresses the brake pedal 10 at the beginning of braking, the motor 114 is actuated, and the rotational force of the motor 114 is converted into a linear motion to press the pressure chamber 111. At this time, the pressure chamber 111 is connected to the reservoir 30 by the inflow channel 116 so as to store the oil. In accordance with the rectilinear motion of the ball screw member 115 that converts the rotational motion into linear motion, . The first and second shutoff valves 143 and 144 provided in the first and second backup flow passages 141 and 142 connected to the outlet of the master cylinder 20 are closed so that the hydraulic pressure generated in the master cylinder 20 And is not transmitted to the cylinder 40. The hydraulic pressure generated from the pressure chamber 111 is transmitted to the wheel cylinders 40 through the first and second hydraulic oil passages 131 and 132, respectively. That is, since the first and second switching valves 133 and 134 are opened by the electronic control unit so as to independently control the hydraulic pressure supplied to the first and second hydraulic circuits 121 and 122, the hydraulic pressure is transmitted Thereby generating a braking force.

The pressure generated by the pressing force of the master cylinder 20 according to the pressing force of the brake pedal 10 is transmitted to the simulation apparatus 150 connected to the master cylinder 20. At this time, the normally closed type simulation valve 155 disposed at the rear end of the simulation chamber 151 is opened, and the oil filled in the simulation chamber 151 through the simulation valve 155 is transferred to the reservoir 30. Further, a pressure corresponding to the load of the reaction force spring 153, in which the reaction force piston 152 is moved and which supports the reaction force piston 152, is formed in the simulation chamber 151 to provide a proper pedal feeling to the driver. Further, when the brake pedal 10 is de-pressurized, the oil is refilled into the simulation chamber 151 through the simulation check valve 157 to ensure a quick return of the pedal simulator 170 pressure.

The electronic brake system according to an embodiment of the present invention includes valves 123, 125, 122 provided in the hydraulic control unit according to the required pressures of the wheel cylinders 40 provided on the respective wheels of the two hydraulic circuits 121, 126, 133, and 134, the control range can be improved. That is, although the above-described hydraulic circuit diagram of FIG. 2 shows the case where braking is performed through the two hydraulic circuits 121 and 122, the braking pressure is selectively applied to only one of the two hydraulic circuits 121, It is possible to control to discharge the braking pressure. 3, the first switch valve 133 provided in the first hydraulic circuit 121 is opened and the first dump valve 125 is closed, so that the wheel cylinder (not shown) of the first hydraulic circuit 121 40 to provide the braking pressure. At the same time, the second switching valve 134 provided in the second hydraulic circuit 122 is closed to shut off the braking pressure to the wheel cylinder 40 of the second hydraulic circuit 122, and the second dump valve 126 So that the pressure of the wheel cylinder 40 flows to the pressure supply device 110 or the reservoir 30. That is, by independently controlling the first and second switching valves 133 and 134 and the first and second dump valves 125 and 126, the hydraulic pressure supplied to the wheel cylinder 40 is controlled according to the required pressure The pressure control performance is improved.

Next, the case where the electronic brake system does not operate normally will be described. 4, when the driver presses the brake pedal 10, the input rod 12 connected to the brake pedal 10 advances to the left, and at the same time, the first piston 21a, which contacts the input rod 12, Will also advance to the left. At this time, since there is no gap between the input rod 12 and the first piston 21a, braking can be performed quickly. That is, the hydraulic pressure generated by pressurizing the master cylinder 20 is transmitted to the wheel cylinder 40 through the first and second backup oil passages 141 and 142 connected for backup braking, thereby realizing the braking force. At this time, the first and second shutoff valves 143 and 144 provided in the first and second backup flow paths 141 and 142 are constituted by normally open type solenoid valves, and the simulation valve 155, As the valves 133 and 134 and the first and second dump valves 125 and 126 are constituted by normally closed solenoid valves, the hydraulic pressure is directly transmitted to the wheel cylinder 40. Therefore, stable braking can be performed and the braking stability can be improved.

The electronic braking system for a vehicle as described above detects the driver's braking intent according to the power of the brake pedal 10 and controls the motor 114 by the output of an electrical signal and converts the rotational motion of the motor 114 into a linear motion The hydraulic pressure can be precisely controlled by controlling the valves 123, 125, 126, 133 and 134 in conjunction with the hydraulic pressure control. In addition, when the brake system according to the present invention fails, the braking oil pressure generated by the driver's power is supplied directly to the wheel cylinder 40 through the backup oil channels 141 and 142, thereby improving the braking stability.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood that various modifications and changes may be made without departing from the scope of the appended claims.

10: Brake pedal 11: Pedal displacement sensor
12: input rod 20: master cylinder
30: Reservoir 40: Wheel cylinder
110: hydraulic pressure supply device 111: pressure chamber
112: pressure piston 113: pressure spring
114: motor 115: ball screw member
116: Inflow channel 117: Check valve
120: Hydraulic control unit 121: First hydraulic circuit
122: second hydraulic circuit 125: first dump valve
126: second dump valve 128: return flow path
131: first hydraulic oil 132: second hydraulic oil
133: first switching valve 134: second switching valve
135: first check valve 136: second check valve
141: first backup channel 142: second backup channel
143: first shutoff valve 144: second shutoff valve
150: Simulation device 155: Simulation valve

Claims

A master cylinder having two hydraulic portions connected to two wheels respectively and coupled to the reservoir to receive oil, and a pedal for sensing the displacement of the brake pedal connected to the input rod which transmits the force according to the driver's power to the piston provided in the master cylinder An electronic brake system comprising a displacement sensor,
A pressure supply device connected to the reservoir by an inflow passage for receiving oil and outputting an operation of the brake pedal through the pedal displacement sensor as an electric signal so as to operate the motor and convert the rotational force of the motor into linear motion;
A hydraulic control unit formed of first and second hydraulic circuits respectively connected to the two hydraulic units, the hydraulic control unit comprising a plurality of valves for controlling the braking operation by receiving hydraulic pressure by a force generated by the pressure supply device;
A simulation device connected to the master cylinder and configured to provide a reaction force in response to the power of the brake pedal; And
And an electronic control unit for controlling the motor and the valves based on the pressure information and the pedal displacement information,
The hydraulic control unit includes:
A valve that is disposed on an upstream side of the wheel cylinders of each wheel to control the delivery of fluid pressure to the wheel cylinders and a valve that is provided in each of the flow paths connecting the pressure supply device and each of the hydraulic circuits, A first switching valve and a second switching valve for controlling the hydraulic pressure, and a second switching valve connected to the downstream side of each of the switching valves and connected to the two wheels and the reservoir in each of the hydraulic circuits, A first and a second dump valve.

The method according to claim 1,
Wherein each of the dump valves is connected to an inlet flow path via a return flow path connected to the reservoir.

The method according to claim 1,
First and second backup oil channels respectively connecting the two hydraulic oil pressure sections and the two oil hydraulic circuits so as to supply oil directly to the wheel cylinder when the electromagnetic brake system operates abnormally, Further comprising first and second shut-off valves for controlling the flow of oil.

The method of claim 3,
Characterized in that the first and second shut-off valves are provided as normally open solenoid valves which are opened in a steady state and operate to close the valve upon receipt of a closing signal in the electronic control unit.

The method according to claim 1,
A first hydraulic oil path connecting the pressure supply device and the first hydraulic circuit, and a second hydraulic oil path branched from the first hydraulic oil path and connecting the second hydraulic circuit,
Wherein the first switching valve is disposed in the first hydraulic oil path and the second switching valve is disposed in the second hydraulic oil path to independently control the hydraulic pressure flowing to each hydraulic circuit.

6. The method of claim 5,
And a check valve is provided in parallel to each of the first and second switching valves.

6. The method of claim 5,
Wherein the first and second switching valves are provided as normally closed solenoid valves which are operated to open the valve when the valve is closed in the normal state and receive an open signal in the electronic control unit.

The method according to claim 1,
The pressure supply device includes:
A pressure chamber connected to the inflow channel and supplied with oil;
A hydraulic piston provided in the pressure chamber;
A hydraulic spring provided in the pressure chamber and elastically supporting the hydraulic piston;
A motor for generating a rotational force by an electrical signal of the pedal displacement sensor; And
And a ball screw member composed of a screw and a ball nut to convert the rotational motion of the motor into a linear motion,
Wherein the hydraulic piston is connected to a ball nut that linearly moves to press the oil in the pressure chamber by a ball nut.

9. The method of claim 8,
Wherein the check valve is installed in the inflow passage so as to prevent the pressure of the pressure chamber from flowing backward and to allow the oil to be sucked into the pressure chamber when the hydraulic piston returns.

9. The method of claim 8,
And a pressure sensor for sensing a pressure is provided in the pressure chamber and the flow path connected to the master cylinder.

9. The method of claim 8,
A cut-off hole is formed in the pressure chamber,
Wherein a connection flow path is formed between the pressure chamber and the inflow path, the connection path being connected to the cutoff hole and the inflow path.

The method according to claim 1,
The simulation apparatus includes:
A simulation chamber for storing oil flowing out from the master cylinder; a pedal simulator having a reaction force piston provided in the simulation chamber and a reaction force spring for elastically supporting the reaction force piston; And
And a simulation valve provided at a rear end of the pedal simulator,
Wherein the simulation valve is connected to a reservoir to fill the interior of the simulation chamber with oil via the simulation valve.

13. The method of claim 12,
Wherein the simulation valve is provided as a normally closed solenoid valve that is operated to open the valve when the valve is closed in the normal state and receives an open signal in the electronic control unit.

13. The method of claim 12,
A simulation check valve is further provided between the pedal simulator and the simulation valve so that the rear end pressure of the pedal simulator according to the power of the brake pedal is transmitted only through the simulation valve and when the pressure of the brake pedal is released, And the oil is sucked and stored in the simulation chamber.

The method according to claim 1,
The master cylinder is provided with first and second pistons spaced apart from each other so as to press the two hydraulic pressure portions, respectively, and the first piston is brought into contact with the input rod so as not to generate a gap between the first piston and the input rod The electronic brake system features.